From: Pavel Tatashin <pasha.tatashin@oracle.com>
To: linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,
linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org,
linux-s390@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
x86@kernel.org, kasan-dev@googlegroups.com,
borntraeger@de.ibm.com, heiko.carstens@de.ibm.com,
davem@davemloft.net, willy@infradead.org, mhocko@kernel.org,
ard.biesheuvel@linaro.org, will.deacon@arm.com,
catalin.marinas@arm.com, sam@ravnborg.org,
mgorman@techsingularity.net, Steven.Sistare@oracle.com,
daniel.m.jordan@oracle.com, bob.picco@oracle.com
Subject: [PATCH v7 10/11] arm64/kasan: explicitly zero kasan shadow memory
Date: Mon, 28 Aug 2017 22:02:21 -0400 [thread overview]
Message-ID: <1503972142-289376-11-git-send-email-pasha.tatashin@oracle.com> (raw)
In-Reply-To: <1503972142-289376-1-git-send-email-pasha.tatashin@oracle.com>
To optimize the performance of struct page initialization,
vmemmap_populate() will no longer zero memory.
We must explicitly zero the memory that is allocated by vmemmap_populate()
for kasan, as this memory does not go through struct page initialization
path.
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
---
arch/arm64/mm/kasan_init.c | 42 ++++++++++++++++++++++++++++++++++++++++++
1 file changed, 42 insertions(+)
diff --git a/arch/arm64/mm/kasan_init.c b/arch/arm64/mm/kasan_init.c
index 81f03959a4ab..e78a9ecbb687 100644
--- a/arch/arm64/mm/kasan_init.c
+++ b/arch/arm64/mm/kasan_init.c
@@ -135,6 +135,41 @@ static void __init clear_pgds(unsigned long start,
set_pgd(pgd_offset_k(start), __pgd(0));
}
+/*
+ * Memory that was allocated by vmemmap_populate is not zeroed, so we must
+ * zero it here explicitly.
+ */
+static void
+zero_vmemmap_populated_memory(void)
+{
+ struct memblock_region *reg;
+ u64 start, end;
+
+ for_each_memblock(memory, reg) {
+ start = __phys_to_virt(reg->base);
+ end = __phys_to_virt(reg->base + reg->size);
+
+ if (start >= end)
+ break;
+
+ start = (u64)kasan_mem_to_shadow((void *)start);
+ end = (u64)kasan_mem_to_shadow((void *)end);
+
+ /* Round to the start end of the mapped pages */
+ start = round_down(start, SWAPPER_BLOCK_SIZE);
+ end = round_up(end, SWAPPER_BLOCK_SIZE);
+ memset((void *)start, 0, end - start);
+ }
+
+ start = (u64)kasan_mem_to_shadow(_text);
+ end = (u64)kasan_mem_to_shadow(_end);
+
+ /* Round to the start end of the mapped pages */
+ start = round_down(start, SWAPPER_BLOCK_SIZE);
+ end = round_up(end, SWAPPER_BLOCK_SIZE);
+ memset((void *)start, 0, end - start);
+}
+
void __init kasan_init(void)
{
u64 kimg_shadow_start, kimg_shadow_end;
@@ -205,8 +240,15 @@ void __init kasan_init(void)
pfn_pte(sym_to_pfn(kasan_zero_page), PAGE_KERNEL_RO));
memset(kasan_zero_page, 0, PAGE_SIZE);
+
cpu_replace_ttbr1(lm_alias(swapper_pg_dir));
+ /*
+ * vmemmap_populate does not zero the memory, so we need to zero it
+ * explicitly
+ */
+ zero_vmemmap_populated_memory();
+
/* At this point kasan is fully initialized. Enable error messages */
init_task.kasan_depth = 0;
pr_info("KernelAddressSanitizer initialized\n");
--
2.14.1
next prev parent reply other threads:[~2017-08-29 2:03 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-29 2:02 [PATCH v7 00/11] complete deferred page initialization Pavel Tatashin
2017-08-29 2:02 ` [PATCH v7 01/11] x86/mm: setting fields in deferred pages Pavel Tatashin
2017-08-29 2:02 ` [PATCH v7 02/11] sparc64/mm: " Pavel Tatashin
2017-08-30 1:09 ` David Miller
2017-08-29 2:02 ` [PATCH v7 03/11] mm: deferred_init_memmap improvements Pavel Tatashin
2017-08-29 2:02 ` [PATCH v7 04/11] sparc64: simplify vmemmap_populate Pavel Tatashin
2017-08-30 1:08 ` David Miller
2017-08-29 2:02 ` [PATCH v7 05/11] mm: defining memblock_virt_alloc_try_nid_raw Pavel Tatashin
2017-08-29 2:02 ` [PATCH v7 06/11] mm: zero struct pages during initialization Pavel Tatashin
2017-08-29 2:02 ` [PATCH v7 07/11] sparc64: optimized struct page zeroing Pavel Tatashin
2017-08-30 1:12 ` David Miller
2017-08-30 13:19 ` Pasha Tatashin
2017-08-30 17:46 ` David Miller
2017-08-29 2:02 ` [PATCH v7 08/11] mm: zero reserved and unavailable struct pages Pavel Tatashin
2017-08-30 21:22 ` kbuild test robot
2017-08-30 23:12 ` kbuild test robot
2017-08-29 2:02 ` [PATCH v7 09/11] x86/kasan: explicitly zero kasan shadow memory Pavel Tatashin
2017-08-29 2:02 ` Pavel Tatashin [this message]
2017-08-29 2:02 ` [PATCH v7 11/11] mm: stop zeroing memory during allocation in vmemmap Pavel Tatashin
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